Shafting for power transmission



Feb. '12, 1935. H. JUNKERS SHAFTING FOR POWER TRANSMISSION Filed Odt. 3, 1931 2 Sheets-Sheet 1 Int glitz:

Feb. 12, 1935. H. JUNKERS SHAFTING FOR POWER TRANSMISSION Filed Oct. 3, 1931 2 Sheets-Sheet 2 lnvenfor; W AMvM/J UNITED STATES PATENT OFFICE SI IAFTlNG Foa rowan TRANSMISSION Hugo .Iunkers, Dessau, Germany, assignor to the firm: Junkers-Motorenbau G. m. b. H., lDessau, Germany Application October 3, 1931, Serial No. 566,690 In Germany, October 11, 1930 Claims. (Cl. 244-25) My invention relates to shafting for power Theduplicate lines need not extend throughout transmission. It is an object of my invention to the power-transmitting system but at least must balance the forces in the shafting. To this end "extend from that portion of the system in which i I subdivide the shafting into two lines for rotareactions on the structures in the shape of bend- 5 tion in opposite directions. ing or torsional stresses would occur without such My invention will be described and illustrated duplication. In this manner the reaction and as applied to the operation of aircraft propellers impelling torques and the gyratory moments ofarranged at some distance from their engines, the two propellers are invariably generated in such aspropellers arranged on Outriggers and pairs of equal intensity but opposite directions other structures which may be connected to the and balance each other with regard to the struc- 10 wings or the fuselage of an airplane or other tures or the like, relieving the structures from aircraft, but it is understood that I am not limforces from'the shafting.

ited to this or any other particular adaptation of In the drawings aflixed to this specification my invention. and forming part thereof an old system of shaft- In mechanisms of this kind as designed hereing and three types of shafting embodying my in- 15 tofore the structures or the like in which the ve tion a e lust ated diagrammatically y y propeller or other rotary driven member is supof comparison and example. ported, are subjected to bending and torsional In the drawings stress'by the torque of the shafting for driving Fig. l is a sectional elevation of a wing with a the propeller, and by the reaction torque of the propeller-supporting structure thereon, s;

propeller. Furthermore gyratory forces occur Fig. 2 is a partly sectional-end elevation of the at the propeller when its axis is displaced in space, W g and t e S uc e, a d

for instance, when flying in a. curve or changing Fig. 3 is a section in plan on the line III-III from horizontal to upward or downward flight, in Fig. 1, showing the old system, and such gyratory forces also generate torsional Fig. 4 is a sectional elevation of a wing and a 1 or bending stress on the structure. Obviously Structure having tW p a ha to W h the structures and the like must be able to tation is impart d by a n rma r p at n nstand all these bending and torsional moments h without undergoing excessive stress and elastic Fig. 5 is a. sectional elevation showing a struc 3o deformation. Conditions are particularly unturevwhich is similarto that illustrated in Fig. favorable if the structures are high, for instance 4, but n which th e g s o the d u t n in seaplanes where the engine is arranged on a type.

float and it is necessary to arrange the propeller Referring now to the drawings and first to Figs. in as high a position as practicable so that it 1 t0 b s the W ng f an airplane, .018 a Strucwill be beyond reach of the waves. Inv such ture on the wing, aild s propel r the-Shaft 35 cases the structure. becomes particularly heavy. i of which is mounted to rotate in a suitable cas- According to my invention the structures or ing 12 at the upper end of the structure 0. d is an other members connecting the energy-consuming engine arranged in the wing 17 on a bed 0. e station, in the present instance, the propeller, is its crank shaft, 11. is a bearing for the outer end do to the energy-producing station, in the present of the crank shaft, f, f are a pair of bevel gears 40 instance, the engine, which structures may be 01 arranged respectively on the crank shaft e ,of .the any kind including wings, engine beds and the engine d and on a vertical intermediate shaft 9 like, are relieved of the stresses-from the forces which is mounted to rotate in a bearing is of a. and movements referred to so that substantially bracket m extending into the wing b from the only fravlty forces and propeller thrust act on the structure 0 at its lower, and in the casing.

structures, and their weight may be reduced in p at its upper end. It is a. bevel gear at the p pfl upper end of the shaft 9 and h is a bevel gear In reducing my invention to practice I provide on the propeller shaft 1' which meshes with the at each power-consuming station two, powerbevel gear h. consuming members, for instance, propellers Referring to Fig. 2, Ma is the reaction torque which rotate in opposite directions and absorb of the propeller a which tends to bend the strucsubstantially equal torques, and for each member ture to. the right as shown greatly exaggerated or propeller I provide a separate line of shaftin Fig. 2. Mg, Fig. 3, is the lmpelling torque of ing with the shafts arranged in parallel, or subthe shaft 11 which is transmitted to the propeller stantially so, and rotating in opposite directions, shaft 2' through the medium of the bevel gears h, h and tends to twist the structure as shown also greatly exaggerated in Fig. 3. The torque of the crank shaft e which is transmitted to the shaft g by the bevel gears ,f, 1' tends to bend the bearing n of the crank shaft e to one side and the bearing k of the vertical shaft 0 to the other side, as shown in Fig. 2, and corresponding reaction torque acts on the engine bed 0. Gyratory moments from the propeller when are caused by altering the direction of the flight, tend to warp or to bend the structure 0 in a similar manner as the torques Ma and My.

These drawbacks are eliminated according to my invention. Referring first to Fig. 4 the wing b with the engine d on the bed 0, the structure 0 and the casing p at its upper endare provided as described with reference to Figs. 1 to 3, but in this instance two propellers a1 and a: are mounted to rotate at opposite ends of the easing p on shafts i1 and i2, respectively.

1' is a frame which is secured to the crank case of the engine n. and is equipped with a bearing for supporting the rear end of ,the crank shaft e. f1 and )z are bevel gears on the crank shaft e which mesh with bevel gears f1 and in on parallel vertical shafts a1 and a2, respectively, the lower ends of which rotate in bearings k1, k: in the frame 1'. The shaft 01 is connected to the shaft ii of the propeller :11 by bevel gears in and hi and the shaft dais connected to the shaft is of the propeller a: by bevel gears ha and ha. By these means rotation in opposite directions is imparted to the shafts g1 and g2 and to the shafts i1 and in, as indicated by the arrows. The torques on the shafts a1 and q: are equal but opposite and therefore balance each other with respect to the structure c so thatthere is no longer any twisting of the structure. Similarly the reaction torques of the oppositely rotating propellers' a1 and a: balance each other so that the only forces acting on the structure 0 are gravity and propeller thrust.

The frame r with the bearings for the crank shaft e and for the vertical shafts a1 and i7: is rigidly connected to the crank case which'prevents the transfer of torques or bending moment to the frame of the airplane. As the engine d and the frame 1' which constitute a single driving unit, transfer to the outside two equal but oppositely directed torques, there will be no longer any reaction torques acting to the outside and all members arranged intermediate the engine bed 0 and the propellers for connecting the engine bed to the propeller bearings, and the engine bed itself, are free of any additional stresses by reaction and impelling torques, and gyratory moments.

Referring to Fig. 5, this arrangement is substantially similar to the arrangement described with reference to Fig. 4, with the exception of the engine. This engine 011 has two-crank shafts 1171 and w: which are connected by a train of spur gears s1, 2:, 2:, 24, the oppositely rotating spur gears 21 and 2: being secured on the. lower ends of the shafts a1 and 9:. This arrangement, like that illustrated in Fig. 4, is without outside torques. r

I wish it to be understood that I do not desire to be limited to the exact details of construction shown and described for obvious modifications will occur to a person skilled in the art.

I claim:

1. In an aircraft a plane body carrying a motor provided with a crank shaft, a housing mounted above said plane body and connected with said body by means of an enclosed structure, propeller shafting mounted in saidhousing and counter shafting mounted in said enclosed structure, the said counter shafting serving to drive said propeller shafting from said crank shaft and comprising two substantially parallel shafts connected to rotate in opposite directions, thereby neutralizing the torques and gyroscopic moments of said counter shafting with respect to said enclosed structure.

2. In an aircraft, an engine provided with at least one crank shaft, two propellers provided with shafts in axial alignment with each other but out of axial alignment with said crank shaft,

two substantially parallel counter shafts driving said propeller shafts from said crank shaft; the two said propellers and propeller shafts, as well as the two said counter shafts rotating in opposite directions; the torques and gyroscopic moments of said counter shafting being thus neutralized with respect to the structure of said aircraft.

3. In an aircraft, a plane body carrying an engine provided with a crank shaft, a housing above said plane'body and an enclosed structure connecting said housing with said plane body, two propellers mounted forwardly and rearwardly of said housing, propeller shafts mounted within said housing and two counter shafts connecting said crank shart with said propeller shafts mounted within said enclosed structure; the two propellers and propeller shafts, as well as the two counter shafts being connected to rotate in opposite directions; thetorques and gyroscopic moments of said counter shafting being thus neutralized with respect to the structure of said aircraft.

4. In an aircraft, an engine, propeller shafting, counter shafting and crank shafting, a framework rigidly attached to the crank case of said engine, at least one bearing for a crank shaft mounted on said framework, two substantially parallel counter shafts driven by said crank shaft in opposite directions and serving to drive said propeller shafting, bearings for said counter shafts mounted on said framework and gearing connecting said crank shaft and saidcounter shafts mounted within said framework.

5. In an aircraft, an engine provided with two crank shafts, two propellers provided with shafts in axial alignment, two substantially parallel counter shafts serving to drive said propeller shafts from said crank shafts with substantially equal torques, the two said propeller shafts, the two said counter shafts and the two said crank shafts rotating in opposite directions, thereby neutralizing the torques and gyroscopic moments of said shafting with respect to the structure of said aircraft. 

